Philips 42PFL3604D/12 - No Power

[budm]

Re: Philips 42PFL3604D/12 - No Power

Those resistors that are fed by the Voltage will not be the one that caused the shorts, the caps and the ICs that are directly (or through low DCR inductors) fed by the Voltage will be the one that I would check.
See example of what I marked.

[paulstef]

Re: Philips 42PFL3604D/12 - No Power

Also U302, the reset monitor IC.

[budm]

Re: Philips 42PFL3604D/12 - No Power

He can also disconnect CN333 if it is used.
BTW there are so many 'NC' so I wonder if some of those parts are used or not on the actual board.

[paulstef]

Re: Philips 42PFL3604D/12 - No Power

Yep. I hope he posts back once he found the problem.

[sententia]

Re: Philips 42PFL3604D/12 - No Power

Hello budm!

I always come back to give feedback...

AV33 has also the same symptoms 2.8ohm resistance to ground.

But U151 is good.

I tried to feed the DV33SB line with some current up to 0.9amps but nothing seemed to get warm or anything.

Do you think i should try to remove the IC's before checking the ceramic caps?

I uploaded the complete service manual in parts.. it is 27mb.

P.S. CN333 and U302 are not populated.

[paulstef]

Re: Philips 42PFL3604D/12 - No Power

Just in case you want to give up, I found one for 35 Euros on ebay.fr

http://www.ebay.fr/itm/Carte-Mere-71...item3cf6da4b13

AV33 comes from +5V_SW which is not yet turned on, right?

Anyway, 2.8 Ohm seems indeed low.

Is DV33SB a real short like 0 Ohm or 0.1Ohm or is it a a few ohms?

You will have to go component by component. Concentrate on semiconductors and ceramic caps that have direct connection to DV33SB and to GND. Resistors don't short (at least I've never seen one).

[paulstef]

Re: Philips 42PFL3604D/12 - No Power

DV33SB later becomes AVDD33 REG which then goes to many other places.

Just a thought. If you pass 1A through a component and it doesn't get warm then it probably has a good heat dissipation capability (or a very low resistance). If the resistance is very low from DV33SB to GND there will be less heat dissipated than if there are a few Ohms. Therefore my question about the resistance from DV33SB to Gnd.

In short : You may not feel any heat because the resistance of the damaged component is so low or because it dissipates heat very well, like the uC with the heatsink on it.

[sententia]

Re: Philips 42PFL3604D/12 - No Power

I have seen the board which is almost the same. LVDS connector is through hole. It is for a 26" so it might need flashing?
Also it does not have the shield around the BGA.

Yes AV33 is not switched on.

AV33 has 2ohms resistance and DV33SB 4ohms.

I also suspect the BGA which is bad news for me really.

Do you think a ceramic capacitor may be shorted? Is it likely?
I might try to remove some but there are a lot in those lines.

[sententia]

Re: Philips 42PFL3604D/12 - No Power

I have tested all caps on DV33SB line and all tested good.

I think it is safe to say that No1 suspect is U400 BGA. Removed the heatsink also to take a pic.

DV33SB and AV33 are associated with U400.

Do you think the mainboard that is for sale would work with this panel straight away?

In service manual it looks like all models from 26" to 42" have the same mainboard. The only visual difference (i noticed) is the LVDS connector and the BGA shield.

Thank you all for the help!

[paulstef]

Re: Philips 42PFL3604D/12 - No Power

Now that the heatsink is removed I would again pass 1A through the DV33SB line.

If it's the BGA it should noticeably heat up.

As for the other board... it may be worth a try.

[sententia]

Re: Philips 42PFL3604D/12 - No Power

I supplied 3V (without resistor this time) bga got shorted for good (1ohm) and extremely hot straight away. I may try to remove the BGA, it can be found around 17e. I don't know if the firmware is stored in the BGA or in the ROM and how they can be programmed. There is a JTAG pad (i don't have a programmer), but also manual mentions a serial interface for the rom.

As for the board for sale, according to manual there is also a resistor difference except FPC LVDS connector.

I found some toshiba models which use exactly the same layout board but with different number on them. Also they have some more features 2x HDMI VGA and spdif out.

[paulstef]

Re: Philips 42PFL3604D/12 - No Power

Removing that chip is something I personally would only try if there was really no other choice. High chance of failure.

To bad that it seems to be the BGA. I have the same problem with another board.

At least we know what it was.

[sententia]

Re: Philips 42PFL3604D/12 - No Power

Hello,

I bought a replacement mainboard for this TV (after attempting to replace the BGA on the original mainboard). The board does work, however i get red pixels noise all around the screen and very high exposure/brightness. Everything looks a bit washed out.

The seller of the mainboard says it is 99% the T-Con card that causes the problem. Is it likely that this is the case?? The T-Con is a LC420/LC470WUN-SBA1.

Any suggestions are welcome.

Thank you all!

[sententia]

Re: Philips 42PFL3604D/12 - No Power

Anyone any ideas??

[sententia]

Re: Philips 42PFL3604D/12 - No Power

I did find a solution finally.

I had to input the 3 digit number printed on the side of the back cover, to "panel type" in service menu SDM.